libtextstyle: Fix test-term-ostream-xterm test failure on TrueOS and Trident.
The xterm description on these platforms includes support for italics.
Reported by Nelson H. F. Beebe.
* libtextstyle/gnulib-local/tests/test-term-ostream-xterm-freebsd-italic.out:
New file.
* libtextstyle/gnulib-local/tests/test-term-ostream-xterm.sh: Use it as possible
expected result.
* libtextstyle/gnulib-local/modules/term-ostream-tests (Files): Add it.
